JPS63128278A - Detector using ultrasonic wave or the like - Google Patents

Abstract

PURPOSE:To increase a detecting speed for an obstacle while having a synchronousless function by setting a transmitting interval of an ultrasonic wave, etc. to a shorter interval than a usual interval by a transmitting timing signal from a controlling circuit when a reflected wave emitted by an object to be detected is received. CONSTITUTION:A transmitter and receiver 5 functioning as a detecting means transmits an ultrasonic wave, an electromagnetic wave, etc., and also, receives a reflected wave by an object to be detected of said ultrasonic wave, etc., and detects the presence of the object to be detected. A detecting and displaying circuit 17 functioning as an informing means informs the presence of the object to be detected based on a detecting signal emitted by this transmitter and receiver 5. A controlling circuit 11 for bringing the transmitting interval of the ultrasonic wave, etc. to variable control receives the reflected wave by the object to be detected and sets the transmitting interval of the ultrasonic wave, etc. to a shorter interval than a usual interval. In such a way, when a detecting device using adjacently many ultrasonic waves, etc. is provided, even if the transmitting interval of the ultrasonic wave, etc. is lengthened as a synchronousless function in order to prevent malfunction due to a mutual interference, it can be prevented that a delay is generated for detecting the presence of the object to be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to measures to prevent malfunctions when a detection device using ultrasonic waves, electromagnetic waves, etc. is provided adjacently.

(Prior Art) Conventional detection devices using ultrasonic waves or electromagnetic waves (hereinafter referred to as ultrasonic waves) may malfunction due to the ultrasonic waves emitted by each other when a large number of such devices are installed nearby. As a countermeasure, synchronous wiring was used to make the timing of emitting ultrasonic waves the same. However, when a large number of ultrasonic detection devices are installed, it is easy to make mistakes in synchronous connection, which causes problems such as malfunctions and damage to the ultrasonic detection devices. As a countermeasure, there are devices that incorporate a synchronization-less function to eliminate the need for synchronous connection, that is, a function that eliminates the need for synchronization of wave transmission timing. One way to obtain this synchronization-less function is to lengthen the ultrasonic transmission interval. However, if this method is used to detect and output the presence or absence of an object to be detected by transmitting ultrasonic waves several times in order to prevent noise, the transmission interval is long, so obstacles may fall within the detection area. A problem arises in that it takes a lot of time to output the detection signal after inputting the signal.

(Objective of the Invention) The present invention provides a synchronization-less function and detects obstacles while providing a synchronization-less function by changing the transmission interval when the detected object (obstacle) changes from a state where there is no object to a state where it is present, or vice versa. An object of the present invention is to provide a detection device using ultrasonic waves or the like that can accelerate object detection speed.

(Structure of the Invention) The present invention provides a detection means for transmitting ultrasonic waves, electromagnetic waves, etc., and receiving reflected waves of the ultrasonic waves from an object to be detected to detect the presence of an object to be detected; The detection device includes a control circuit that variably controls the transmission interval of ultrasonic waves or the like, and this control circuit is configured to detect the presence of a detection object based on a detection signal from the detection device. It receives waves and makes the transmission interval of ultrasonic waves etc. shorter than the normal interval.

(Example) An embodiment of the present invention will be described with reference to FIG.

The oscillation circuit 1 oscillates a signal of 40 KHz (this is just an example; other frequencies of 32.6 KHz are also possible), which is the same frequency as the ultrasonic wave.

The AND gate 2 receives the 40 KHz signal from the oscillation circuit 1 and the gate signal B from the gate signal generation circuit 3 for 111 seconds and performs an AND operation.

lll1sec, the gate signal generation circuit 3 is connected to the control circuit 1
1 m5ec after receiving the transmission timing signal A from 1.

It outputs a gate signal B of .

The drive circuit 4 amplifies the 40 KHz burst wave C and drives the ultrasonic transducer 5.

The ultrasonic transducer (detection means) 5 is equipped with a sensor horn that emits an electric signal from the drive circuit 4 into the air as an ultrasonic wave. For example, when there is a detection object such as an obstacle, the ultrasonic wave reflected by the obstacle is received and converted into an electrical signal. The ultrasonic transducer 5 may be configured to transmit and receive waves separately.

The amplifier circuit 6 amplifies the signal from the ultrasonic transducer 5 to a level at which the next circuit operates.

The bandpass filter circuit 7 passes only the frequency of 40 KHz, which is the same as the ultrasonic wave, from the received signal.

When the waveform shaping circuit 8 receives a signal of a certain level or higher,
It outputs a high (H) level signal.

The AND gate 9 is connected to the detection area gate signal generation circuit 1.
When the detection area gate signal E from 0 is at a high (H) level, the received signal from the waveform shaping circuit 8 is output.

The in-detection area gate signal generation circuit 10 outputs a high (H) level for a period of time corresponding to the distance from the sensor horn exit to the maximum distance at which a detection object can be detected.

The control circuit 11 outputs a transmission timing signal A and a shift clock G. This control circuit 11 includes an OR gate 1
When receiving a high (H) level signal from the OR gate 14, the period of the transmission timing signal A is shortened, and when receiving a low (L) level signal from the OR gate 14, the period of the transmission timing signal A is shortened. It is something that lengthens the.

The shift circuit 12 stores the received signal F from the AND gate 9, and when the shift clock G from the control circuit 11 is input, outputs the stored received signal to the terminal Q1. This output signal is set to H. When the next shift clock G is input, the stored reception signal is shifted and outputted to the terminal Q2. Let this output signal be I.

The AND gates 13-1 and 13-2 output the AND of the output signals H and I from the shift circuit 12. Let these output signals be J.

The OR gate 14 outputs the OR of the signals from the AND gates 13-1 and 13-2. Let this = 6- output signal be L.

The AND gates 15-1 and 15-2 output the AND of the output signals H and I from the shift circuit 12.

The flip circuit flop circuit 16 has an AND gate 15-1.
When it receives a high level signal M from the AND gate 15-2, it outputs a high level signal O, and when it receives a high level signal N from the AND gate 15-2, it outputs a low level signal O.

When the detection display circuit (notification means) 17 receives a high (H) level signal O from the flip-flop circuit 16, it notifies the user of the presence of the detected object, and the flip-flop circuit 1
When a low (L) level signal O is received from 6, the user is informed that there is no object to be detected. In addition, the shift circuit 12, AND gate 15-1, 15-2, flip
The flop circuit 16 constitutes a delay means for sending the output of the detection display circuit 17.

Next, the operation of the ultrasonic detection device having the above configuration will be explained with reference to FIG. 2.

First, the operation when there is no detection object within the detection area will be explained. This state corresponds to area (3) in FIG.

The gate signal generation circuit 3 receives the transmission timing signal A output from the control circuit 11 at 1m5e.
c, outputs a high (H) level gate signal B. Then, the signal B and the 40 KHz signal from the oscillation circuit 1 enter an AND gate 2, and a 40 KHz burst wave C is output. The drive circuit 4 amplifies the signal C, and the ultrasonic transducer 5 emits ultrasonic waves into the air. The ultrasonic waves output by the ultrasonic transducer 5 do not return as reflected waves because there is no detection object. Therefore, the ultrasonic transducer 5 does not output an electric signal. Therefore, the amplifier circuit 6 and the bandpass filter circuit 7 do not output electrical signals, so the waveform shaping circuit 8 does not output electrical signals. AND gate 9
is the signal and the detection area gate signal generation circuit 10
The high (H) level in-detection area gate signal E is ANDed and a low (L) level signal F is output.

The shift circuit 12 stores the received signal (low level) F, and when the shift clock G from the control circuit 11 is input, the output signal H at the terminal Q1 becomes low level.

Here, if there was no detected object within the detection area last time,
The output signal of terminal Q2 is also at low level, and both output signals H and I are at low level, so AND gate 13
-1, 13-2 all output a low level signal, and the OR gate 14 outputs a low level signal. In response, the control circuit 11 lengthens the period of the next wave transmission timing signal A as shown in FIG. 2 and outputs it. AND gate 15-1
Since the inputs (output signals H, I) are low level, outputs a low level signal M. AND gate 15-2 is
Since the inputs (output signals H, I) are at low level, a high level signal N is output. In response, the flip-flop circuit 16 outputs a low level signal O. In response to this, the detection display circuit 17 notifies the user that there is no detected object.

Next, the operation when a detection object enters the detection area will be explained. This state corresponds to area (3) in FIG.

The control circuit 11 outputs a wave transmission timing signal A. Then, the same operation as described above is performed, and the ultrasonic transducer 5 emits ultrasonic waves into the air. The ultrasonic waves output by the ultrasonic transducer 5 return as reflected waves because there is a detection object.

Therefore, the ultrasonic transducer 5 outputs an electric signal.

Among the ultrasonic transmission and reception signals in FIG. 2, Di and D2 indicate reflected waves from obstacles. The signal is amplified by an amplifier circuit 6, noise is removed by a bandpass filter circuit 7, and converted into an H level signal by a waveform shaping circuit 8. This signal and the detection area gate signal (high level) E enter an AND gate 9, and this gate 9 outputs a high level signal F. The shift circuit 12 receives the received signal (high level) F.
is stored, and when the shift clock G from the control circuit 11 is input, the terminal Q1 outputs a high level output signal H.

Here, last time, there was no detected object within the detection area, so
Terminal Q2 outputs a low level.

= 10- Therefore, the AND gate 1B-2 outputs a low level signal K, but the AND gate 13-1 outputs a high level signal J. Then, the OR gate 14 outputs a high level. In response to this, the control circuit 11 outputs the frequency of the next transmission timing signal A at a shorter frequency as shown in FIG. AND gate 15-1.15-2 has one input (
Output signal H) is high level, the other input (output signal I)
Since it is at a low level, low level signals M and N are output. In response, the flip φ flop circuit 16 continues to output a low level, and at this point the display circuit 17 does not yet notify the user that there is a detected object.

When the control circuit 11 shortens the cycle and outputs the next transmission timing signal A, the same operation as described above is performed, and the AND gate 9 outputs a high level signal F'. Shift circuit 1
2 stores the received signal (high level) F, and when the shift clock G from the control circuit 11 is input, the terminal Q1 outputs a high level output signal H. Last time, terminal Q1 was outputting a high level, so this time, terminal Q1 outputs a high level.
2 outputs a high level output signal I. Therefore, A
ND gates 1B-1, 13-2 output low level signals J and K. Then, the OR gate 14 outputs a low level signal. In response to this, the control circuit 11 lengthens the period of the next wave transmission timing signal A as shown in FIG. 2 and outputs it. Since the inputs (output signals H, I) of the AND gate 15-1 are high level, the AND gate 15-1 receives the high level signal M.
Output.

In response to this, the flip-flop circuit 16 outputs a high level signal O. As a result, the detection display circuit 17 notifies the user that there is a detected object.

Continuously, when there is a detection object within the detection area, the OR gate 14 outputs a low level. In response to this, the control circuit 11 outputs the transmission timing signal A with a longer period, so that the ultrasonic transducer 5 continues to output ultrasonic waves at a longer period. In this way, the transmission interval of the transmission timing signal A is shortened only when the reception signal F is received.

Next, the operation when there is no detection object within the detection area will be explained. This state corresponds to area (3) in FIG.

The control circuit 11 outputs a wave transmission timing signal A. Then, the same operation as described above is performed, and the waveform shaping circuit 8 does not output an electrical signal. The AND gate 9 ANDs this signal and the high (H) level detection area gate signal E from the detection area gate signal generation circuit 10, and outputs a low (L) signal.
) Output the level. The shift circuit 12 stores the received signal (low level), and when the shift clock G from the control circuit 11 is input, the terminal Q1 outputs a low level output signal H. Last time, there was a detection object within the detection area, so the terminal Q2 outputs a high-level output signal ■. Therefore, the AND gate 113-1 outputs a low level signal J, the AND gate 13-2 outputs a high level signal K, and the OR gate 14 outputs a high level signal.

After that, the control circuit 11 generates the next wave transmission timing signal A.
The period is shortened as shown in FIG. 2 and output. AND
Gate 15-1.15-2 has one input (output signal H)
is low level and the other input (output signal ■) is high level, so low level signals M and N are output. In response, the flip-flop circuit 16 outputs a high level signal O.
continues to be output, and at this point, the detection display circuit 17 does not yet notify the user that the detected object is gone.

When the control circuit 11 shortens the cycle and outputs the next transmission timing signal A, the same operation as described above is performed, and the AND gate 9 outputs the low level signal F. Shift circuit 12
stores the received signal (low level) F, and when the shift clock G from the control circuit 11 is input, the terminal Q
1 outputs a low level output signal H. Last time, terminal Q
1 was outputting a low level, the terminal Q2 outputs a low level output signal I. Therefore, the AND gates 13-1 and 132 receive the low level signal J.

Output K. Then, the OR gate 14 outputs a low level signal. In response to this, the control circuit 11 lengthens the period of the next wave transmission timing signal A and outputs it. AND
Since both inputs to the gate 15-2 are at a low level, the gate 15-2 outputs a signal N at a high level. In response to this, the flip-flop circuit 16 outputs a low level signal O. As a result, the detection display circuit 17 notifies the user that the object to be detected is gone.

Continuously, when there is no object to be detected within the detection area, the OR gate 14 outputs a low level signal.

In response to this, the control circuit 11 outputs the transmission timing signal A with a longer period, so that the ultrasonic transducer 5 continues to output ultrasonic waves at a longer period. In this way, even when there is no received signal, the transmission interval of the transmission timing signal A is shortened.

The ultrasonic detection device repeats the above operation.

As described above, the ultrasonic detection device includes the shift circuit 12, AN
By the transmission interval signals output by the D gates 13-1, 13-2 and the OR gate 14, and the operation of the control circuit 11, it is detected that the state where there is no obstacle changes to the state where there is an obstacle. , shorten the ultrasound transmission interval. Therefore, it is possible to detect and output the presence of an obstacle earlier by the time corresponding to the shorter transmission interval.

Through a similar function, when the state changes from a state where there is an obstacle to a state where there is no obstacle, the ultrasonic detection device shortens the ultrasonic transmission interval and quickly detects that the obstacle is gone by the shortened time. It can be detected and output.

Furthermore, due to the functions of the AND gates 15-1 and 15-2 and the flip-flop circuit 16, the detection display signal P is output after the second reception signal F is received, so there is a delay in output. However, malfunctions due to noise can be prevented.

FIG. 3 shows the configuration of a first embodiment of the oscillation circuit 11 that changes the transmission interval, and FIG. 4 shows its operating waveforms.

This control circuit 11 is composed of an oscillator 101, an up counter 102, a flip-flop circuit 103, AND gates 104, 105, and an OR gate 106.
The output signals Q1 to Q4, the transmission interval control signal, the output signals 22 and 23 of the AND gates 104 and 105, the transmission timing signal A and the reset signal 24 are as shown in FIG. The transmission interval is long when the transmission interval control signal is at a low level, and conversely becomes short when the transmission interval control signal is at a high level.

Similarly, the configuration of the second embodiment of the control circuit 11 is shown in FIG. 5, and its operating waveforms are shown in FIG. This control circuit 11 includes a transistor 105, comparators 106 and 107,
AND gate 108. 109
, OR gate 110, etc., and OR gate 11
A sawtooth wave signal 31 is obtained by a transistor 105, a resistor, and a capacitor, which are controlled by feeding back the transmission timing signal A, which is the output of 0, and this signal is sent to a comparator 106. '107 input. These signals and the output signals 32.3 of comparators 106, 107
B, transmission interval control signal L1AND gate 108.109
The gate output signals 34 and 35 are as shown in Fig. 6, and the transmission interval of the transmission timing signal A is long when the transmission interval control signal is low level, and conversely, when the transmission interval control signal is low level, the transmission interval of the transmission timing signal A is long. It gets shorter at higher levels.

In this way, the transmission interval of the transmission timing signal A can be variably controlled depending on the level of the transmission interval control signal.

Note that although an example using ultrasonic waves has been shown above, electromagnetic waves may be used in addition to ultrasonic waves.

(Effects of the Invention) As described above, according to the present invention, when a reflected wave from a detected object is received, the transmission interval of ultrasonic waves becomes shorter than the normal interval, and this transmission interval becomes shorter only when changing from a state with no detected object to a state with a detected object, and from a state with a detected object to a state without a detected object, so the The response speed for detecting the presence or absence of a sensing object can be increased.

In other words, by increasing the transmission interval of ultrasonic waves, etc. as a synchronizationless function to prevent malfunctions due to mutual interference when a large number of detection devices using ultrasonic waves, etc. are installed adjacently, the detected object This has the effect of preventing delays in detecting the presence of.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a detection device using ultrasonic waves or the like according to an embodiment of the present invention, FIG. 2 is a time chart for explaining the operation of the device, and FIG. 3 is a diagram of a control circuit in the device. 4 is a time chart for explaining the operation of the first embodiment, FIG. 5 is a block diagram showing the second embodiment of the control circuit, and FIG. 6 is the operation of the same embodiment. It is a time chart for explaining. 5... Ultrasonic transducer (detection means), 11... Control circuit, 12... Shift circuit (delay means), 13-1゜13-2... AND gate, 14... OR Gate,
15-1.15-2...AND gate, 16...Flip-flop circuit (delay means), 17...Detection display circuit (notification means). Patent applicant Matsushita Electric Works Co., Ltd. 41, S-shaped No. 31 Con/Greke 1 No. 32 Connog Retai t also 33 Lotus gap-1fIIP1 No. L ANoy-to body No. 3+ AND Two Toy Sn No. 35

Claims (1)

[Claims] 1. A detection means for transmitting ultrasonic waves, electromagnetic waves, etc., and receiving reflected waves of the ultrasonic waves from an object to be detected to detect the presence of the object to be detected, and this detection means A detection device is equipped with a control circuit that variably controls the transmission interval of ultrasonic waves, etc., and this control circuit detects the reflected waves from the detected object. A detection device using ultrasonic waves or the like, characterized in that the transmission interval of ultrasonic waves or the like is shorter than the normal interval by receiving the waves. 2. The detection device using ultrasonic waves or the like according to claim 1, wherein the detection means is an ultrasonic transducer. 3. A detection device using ultrasonic waves or the like according to claim 1, further comprising a delay means for delaying the output to the notification means.